This paper investigates the temperature-dependent performances of AlGaN/GaN metal-oxide-semiconductor high electron mobility transistor (MOS-HEMT). The gate dielectric layer and surface passivation ...layer are formed by the H 2 O 2 oxidation technique. The gate dielectric quality is estimated by the breakdown electric field (EBD) and low-frequency noise. The capacitance-voltage (C-V) hysteresis characteristics of MOS and Schottky diodes at 300/480 K are also studied. An appropriate thermal model is used to investigate the self-heating effect and calculate the effective channel temperature (T eff ). The dc performances of the present MOS-HEMT are improved at 300/480 K, as compared with a Schottky-barrier HEMT (SB-HEMT), including output current density, maximum extrinsic transconductance (gm,max), gate voltage swing, gate-drain leakage current (IGD), specific ON-resistance (RON), three-terminal OFF-state breakdown voltage (BVOFF), and subthreshold swing. Factors that cause IGD and BVOFF are analyzed by the temperature-dependent measurement. The passivation effect of the present MOS-HEMT is also confirmed by the surface leakage measurement. The devised MOS-HEMT demonstrates superior thermal stability to the reference SB-HEMT. The present-design is promising for high-temperature electronic applications.
T cell polyfunctionality is a hallmark of protective immunity against pathogens and cancer, yet the molecular mechanism governing it remains mostly elusive. We found that canonical Wnt agonists ...inhibited human memory CD8+ T cell differentiation while simultaneously promoting the generation of highly polyfunctional cells. Downstream effects of Wnt activation persisted after removal of the drug, and T cells remained polyfunctional following subsequent cell division, indicating the effect is epigenetically regulated. Wnt activation induced a gene expression pattern that is enriched with stem cell-specific gene signatures and upregulation of protein arginine methyltransferase 1 (PRMT1), a known epigenetic regulator. PRMT1+CD8+ T cells are associated with enhanced polyfunctionality, especially the ability to produce IL-2. In contrast, inhibition of PRMT1 ameliorated the effects of Wnt on polyfunctionality. Chromatin immunoprecipitation revealed that H4R3me2a, a permissive transcription marker mediated by PRMT1, increased at the IL-2 promoter loci following Wnt activation. In vivo, Wnt-treated T cells exhibited superior polyfunctionality and persistence. When applied to cytomegalovirus (CMV) donor-seropositive, recipient-seronegative patients (D+/R-) lung transplant patient samples, Wnt activation enhanced CMV-specific T cell polyfunctionality, which is important in controlling CMV diseases. These findings reveal a molecular mechanism governing T cell polyfunctionality and identify PRMT1 as a potential target for T cell immunotherapy.
The large-scale atmospheric circulation of the North Pacific associated with two types of El Niño—the eastern Pacific (EP) and central Pacific (CP)—is studied in relation to Hawaiian winter ...(December–February) rainfall and temperature. The eastern and central equatorial Pacific undergo active convective heating during EP El Niño winters. The local Hadley circulation is enhanced and an upper-level westerly jet stream of the North Pacific is elongated eastward. Due to the impact of both phenomena, stronger anomalous descending motion, moisture flux divergence anomalies near Hawaii, and reduction of easterly trade winds, which are characteristic of EP winters, are unfavorable for winter rainfall in Hawaii. As a result of this robust signal, dry conditions prevail in Hawaii and the standard deviation of rainfall during EP winters is smaller than the climatology. For CP winters, the maximum equatorial ocean warming is weaker and shifted westward to near the date line. The subtropical jet stream retreats westward relative to EP winters and the anomalously sinking motion near Hawaii is variable and generally weaker. Although the anomalous moisture flux divergence still exists over the subtropical North Pacific, its magnitude is weaker relative to EP winters. Without strong external forcing, rainfall in the Hawaiian Islands during CP winters is close to the long-term mean. The spread of rainfall from one CP event to another is also larger. The near-surface minimum temperature from three stations in Hawaii reveals cooling during EP winters and slight warming during CP winters.
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Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The present study investigated the oncologic outcomes of clinical stage IA2 non-small cell lung cancer (NSCLC) treated using preoperative simulation and surgical resection.
Data of patients who ...underwent surgical resection for clinical stage IA2 NSCLC between January 2002 and June 2018 were reviewed. Preoperative simulations were indicated for patients with centrally located tumors who could undergo anatomic resection. Clinical features, imaging characteristics of the tumors, surgical approaches, and outcomes were analyzed.
Of the 1086 identified patients, 281 patients with clinical stage IA2 NSCLC were enrolled and categorized into 2 groups, with and without preoperative simulation. Tumor location, maximum standard uptake value, histologic grade, disease-free survival, and disease recurrence were significantly different between the 2 groups. For patients with preoperative simulations, 70.7% underwent anatomic resection, whereas for patients without preoperative simulations, 79.7% underwent anatomic resection (P < .001). Patients with preoperative simulations had fewer relapses (2%) than patients without preoperative simulations (11.5%, P < .01).
Preoperative simulation confirmed the relationship between the tumor and surrounding blood vessels and bronchus and ensured an oncologic safety margin. Three-dimensional simulations are a useful and feasible tool for planar operative procedures and satisfy the requirements for early-stage NSCLC. These results are promising but preliminary, and more extended follow-up is needed.
This paper investigates enhanced device characteristics of AlGaN/GaN metal-oxide-semiconductor high electron mobility transistor (HEMT) (MOS-HEMT) fabricated by using hydrogen peroxide (H 2 O 2 ) ...oxidation technique which demonstrates the advantages of simplicity and cost effectiveness. A 13-nm-thick Al 2 O 3 oxide was grown upon the surface of AlGaN barrier layer and served as the gate dielectric layer and the surface passivation layer at the same time to effectively decrease gate leakage current and prevent RF current collapse, which are the critical issues of nitride HEMTs. Enhanced device performances of dc, RF, power, and reliability of the present MOS-HEMT are comprehensively investigated as compared with a conventional Schottky-gate HEMT.
Cytomegalovirus (CMV) infection is one of the most common persistent viral infections in humans worldwide and is epidemiologically associated with many adverse health consequences during aging. ...Previous studies yielded conflicting results regarding whether large, CMV-specific T-cell expansions maintain their function during human aging. In the current study, we examined the in vitro CMV-pp65-reactive T-cell response by comprehensively studying five effector functions (i.e., interleukin-2, tumor necrosis factor-α, interferon-γ, perforin, and CD107a expression) in 76 seropositive individuals aged 70 years or older. Two data-driven, polyfunctionality panels (IL-2-associated and cytotoxicity-associated) derived from effector function co-expression patterns were used to analyze the results. We found that, CMV-pp65-reactive CD8 + and CD4 + T cells contained similar polyfunctional subsets, and the level of polyfunctionality was related to the size of antigen-specific response. In both CD8 + and CD4 + cells, polyfunctional cells with high cytotoxic potential accounted for a larger proportion of the total response as the total response size increased. Notably, a higher serum CMV-IgG level was positively associated with a larger T-cell response size and a higher level of cytotoxic polyfunctionality. These findings indicate that CMV-pp65-specific CD4 + and CD8 + T cell undergo simultaneous cytotoxic polyfunctionality maturation during aging.
Comparative studies for TiO 2 -passivated Al 0.25 Ga 0.75 N/GaN heterostructure FETs (HFETs) and TiO 2 -dielectric MOS-HFETs using nonvacuum ultrasonic spray pyrolysis deposition technique are made. ...Optimum device performances are obtained by tuning the layer thickness of TiO 2 to 20 nm. High relative permittivity (k) of 53.6 and thin effective oxide thickness of 1.45 nm are also obtained. Pulse-IV, Hooge coefficient (α H ), Transmission Electron Microscopy, and atomic force microscope have been performed to characterize the interface, atomic composition, and surface flatness of the TiO 2 oxide. Superior improvements for the present TiO2dielectric MOS-HFET/TiO 2 -passivated HFETs are obtained, including 47.6%/23.8% in two-terminal gate-drain breakdown voltage (BV GD ), 111%/22.2% in two-terminal gate-drain turnON voltage (V ON ), 47.9%/39.4% in ON-state breakdown (BV DS ), 12.2%/10.2% in drain-source current density (I DS ) at V GS = 0 V (I DSS0 ), 27.2%/11.7% in maximum I DS (I DS,max ), 3/1-order enhancement in ON/OFF current ratio (I ON /I OFF ), 58.8%/17.6% in gate-voltage swing linearity, 25.1%/13.2% in unity-gain cutoff frequency (f T ), 40.6%/24.7% in maximum oscillation frequency (f max ), and 33.8%/15.6% in power-added efficiency with respect to a Schottky-gated HFET fabricated on the identical epitaxial structure. The present MOS-HFET has also shown stable electrical performances when the ambient temperature is varied from 300 to 450 K.
This study examined the physicochemical effects of the fortification of noodles with 0.25-1.00% (
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) calcium salts, viz. calcium acetate, calcium carbonate, calcium citrate, and calcium lactate. ...Fortification with calcium citrate, calcium acetate, and calcium carbonate increased the pH and breaking force of the dried noodles. However, the fortification of noodles with any concentration of calcium did not increase the extent of elongation of the control raw noodles. The L* and b* values of the raw and dried noodle color increased with increasing concentrations of calcium salts, except for noodles with added calcium citrate. Fortification with calcium citrate yielded no significant influence on color, texture, adhesiveness, springiness, flavor, and overall scores for cooked noodles. Noodles fortified with 0.5% calcium citrate made from oyster shells were compared with a control sample of noodles and noodles fortified with commercially available calcium citrate. The particle size of the calcium citrate made from oyster shells (258 nm) was smaller than that of the purchased calcium citrate (2631 nm). Noodles fortified with calcium citrate made from oyster shells showed no significantly difference compared to noodles fortified with commercially available calcium citrate. These results suggest that calcium citrate made from oyster shells may be used as the additive of choice for the manufacture of calcium-fortified noodles.
High-k TiO 2 -dielectric Al 0.25 Ga 0.75 N/GaN metal-oxide-semiconductor high-electron mobility transistors (MOS-HEMTs) grown on Si substrates by using nonvacuum ultrasonic spray pyrolysis deposition ...technique are reported for the first time. The effective oxide thickness is 1.45 nm with layer thickness/dielectric constant of 20 nm/53.6. Pulse I-V and low-frequency noise spectra (1/f) are conducted to characterize the interface property. The gate leakage current I GD is decreased by three orders at V GD = -50 V as compared with a reference Schottky-gate device. Superior device characteristics are achieved for the present MOS-HEMT (Schottky-gate HEMT) for the gate dimensions of 1 μm × 100 μm including drain-source current density I DS at V GS = 0 V (I DSS0 ) of 384 (342) mA/mm, maximum I DS (I DS , max ) of 650 (511) mA/mm, maximum extrinsic transconductance (g m , max ) of 107 (110) mS/mm, two-terminal gate-drain breakdown voltage (BVGD) of -155 (-105) V, turn-ON voltage (VON) of 3.8 (1.8) V, ON-state breakdown (BVDS) of 139 (94) V, gate-voltage swing of 2.7 (1.7) V, and ON/OFF current ratio (I ON /I OFF ) of 4.5 x 10 5 (3.5 x 10 2 ).
Al 0.3 Ga 0.7 N/AlN/GaN metal-oxide-semiconductor high electron mobility transistors (HEMTs) grown on Si substrates by using ozone water oxidation method are investigated. Superior improvements of ...52.2% in two-terminal gate-drain breakdown voltage (BV GD ), 30.3% in drain-source current density (I DS ) at V GS = 0 V (I DSS0 ), 43.6% in maximum I DS (I DS,max ), 34.7% in maximum extrinsic transconductance ( gm ,max), and 52.7%/34.3% in unity-gain cutoff/maximum oscillation frequency ( fT / f max ) are achieved as compared with a reference Schottky-gated HEMT. Thermal stability is studied by conducting temperature-dependent characterizations of devices at ambient temperatures of 300-550 K. Time-dependent electrical reliability analyses for the devices stressed in off-state (V GS = -20 V and V DS = 0 V) for 0-60 h and on-state (V GS = 2 V and V DS = 20 V) for 0-20 h are also made to physically investigate the dominant degradation mechanisms. Excellent reliability and thermal stability at 300-550 K are achieved by the present design.
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